A reorientation of the PO3-groups and radiation damage effect in ferroelectric phase transition studied by CW-EPR of PO32- radical in glycine·H3PO3 single crystal

EPR of γ-ray generated PO₃^2- radicals indicates that the four radical centers are equivalent in the paraelectric phase and become inequivalent in the ferroelectric phase due to a ±3° rotation. The phase transition temperature is shifted by irradiation from T_c = 224 K to T_c = 180 K. The molecular mechanism of the order-disorder phase transition is discussed     

An Automatic Hierarchical Delay Analysis Tool

The performance analysis of VLSI integrated circuits(ICs) with flat tools is slow and even sometimes impossible to complete.Some hierarchical tools have been developed to speed up the analysis of these large ICs.However,these hierarchical tools suffer from a poor interaction with the CAD database and poorly automatized operations.We introduce a general hierarchical framework for performance analysis to solve these problems.The circuit analysis is automatic under the proposed framework.Information that has been automatically abstracted in the hierarchy is kept in database properties along with the topological information.A limited software implementation of the framework,PREDICT,has also been developed to analyze the delay performance.Experimental results show that hierarchical analysis CPU time and memory requirements are low if heuristics are used during the abstraction process.     

A dynamic reconfiguration scheme for mega bit Static Random Access Memories

The objective of this paper is to present a novel dynamic reconfiguration scheme for mega bit Static Random Access Memories (SRAMs). Most of the conventional reconfiguration methods are implemented using two-way switching elements. The proposed scheme is based on on-chip word failure detection and reconfiguration to spare word cell using multi-valued logic elements. The physical concept of the dynamic reconfiguration scheme and implementation details are discussed. Based on the SRAM dynamic reconfiguration implementation a reliability model is develoed. Dyanamic reconfiguration scheme reliability comparisons with other existing methods are presented. The advantages of the proposed dyanamic reconfiguration scheme are highlighted.     

Effect of nanopore geometry on ion current rectification

We present the results of systematic studies of ion current rectification performed on artificial asymmetric nanopores with different geometries and dimensions. The nanopores are fabricated by the ion track etching method using surfactant-doped alkaline solutions. By varying the alkali concentration in the etchant and the etching time, control over the pore profile and dimensions is achieved. The pore geometry is characterized in detail using field-emission scanning electron microscopy. The dependence of the ion current rectification ratio on the pore length, tip diameter, and the degree of pore taper is analysed. The experimental data are compared to the calculations based on the Poisson-Nernst-Planck equations. A strong effect of the tip geometry on the diode-like behaviour is confirmed.     

A Unity Gain High Speed Buffer to Improve Signal Integrity in High Frequency Test Interface

The availability of faster electronic components allows the design of more effective and efficient test equipments. However in high-speed applications, the effect of interconnects between the tester and the device under test DUT introduces ringing, overshoot and timing delay problems. In this paper we present an output high speed buffer which helps to cancel the overshoot, undershoot, and ringing. The buffer which has a unity gain, presents a high output current and introduces small delay. It is able to drive the comparator of the tester through the transmission line with minimum distortion of the signal. Compared with other approaches, the use of this output buffer provides good improvement of the signal. This output buffer which is designed for the interface between tester and DUT can be considered for communication between high speed devices in printed circuits boards. The calibration procedure is explained in order to determine the delay introduced by the buffer and to measure low and high voltage levels of the digital output signal of the buffer.     

The amine modified acrylonitrile-divinylbenzene copolymers in the phase transfer catalysis

Summary Amine modified, macroporous acrylonitrile-divinylbenzene copolymers of various crosslinking degree were used as catalysts in the reaction of octylbromide with cyano anions.The dependence of their catalytic activity upon swelling and strongly basic amino groups content were discussed.The reaction rate constants were somewhat lower than those for the reactions catalysed by other polymers containing tributylammonium groups.lt was probably due to the presence of ordered regions in copolymers containing large amounts of acrylonitrile units.This work was presented in part at the 30th Microsymposium on Macromolecules, Prague, July 1987     

Dielectric and TSC study of semicompatible PVDF/PMMA blends

Summary Dielectric and TSC studies of charged (by stabilized electrical breakdown) and discharged PVDF/PMMA blends have been performed. The relative changes in are found to decrease with increasing PVDF content except for samples with 50 and 70 weight-% of PVDF. The temperature T_max of the TSC maximum is found to be shifted linearly towards lower temperatures with increasing PVDF content up to 30 weight-% of PVDF. For higher concentrations T_max is found to be independent on PVDF content except for samples of 70 weight-% of PVDF. These behaviours indicate that for PVDF concentrations higher than 30 weight-% the system starts to lose its compatibility.     

Non-thermal plasma treatment as a new biotechnology in relation to seeds,dry fruits,and grains

Non-thermal plasma(NTP) technology offers wide potential use in the food technology, the same as in the unconventional agriculture. Some seeds, dry fruits, grains and their sprouts gain popularity in the culinary industry as ‘raw seeds'. This review paper draws the current research and trends in NTP pre-treatment of selected seeds/fruits that are useable as ‘raw seeds'. The main applications are connected with activation of seed germination, early growth of seedlings,microbial inactivation of seed/fruit surface, and possibility of increasing quantity of biological active compounds in sprouting seeds. The paper presents a list of plant species that are able to be used as ‘raw seed' including current information about main type of NTP treatment implemented.     

Germination of Chenopodium Album in Response to Microwave Plasma Treatment

The seeds of Lamb＇s Quarters （Chenopodium album agg.） were stimulated by low- pressure discharge. The tested seeds were exposed to plasma discharge for different time durations （from 6 minutes to 48 minutes）. Germination tests were performed under specified laboratory conditions during seven days in five identical and completely independent experiments. Significant differences between the control and plasma-treated seeds were observed. The treated seeds showed structural changes on the surface of the seat coat. They germinated faster and their sprout accretion on the first day of seed germination was longer. Germination rate for the untreated seeds was 15% while it increased approximately three times （max 55%） for seeds treated by plasma from 12 minutes to 48 minutes.